Chronic interstitial pneumonitis in end-stage sarcoidosis

Abstract

To the Editors: End-stage sarcoidosis is typically characterised by severe interstitial fibrosis occurring along the bronchovascular bundles with cystic changes 1, 2. Chronic interstitial pneumonitis typically occurs in the early stages of sarcoidosis and is localised to the areas affected by granulomas 3–5. Herein, we report end-stage sarcoidosis patients who underwent lung transplantation at our centre (University of Southern California, Keck School of Medicine, Los Angeles, CA, USA) and who surprisingly had evidence of moderate-to-severe chronic interstitial pneumonitis, which was previously considered atypical in end-stage sarcoidosis. Furthermore, two patients had a pattern resembling usual interstitial pneumonitis (UIP) with fibroblastic foci. We reviewed the charts and microscopic slides of all sarcoidosis patients who underwent lung transplantation at the University of Southern California. Patients were only included if the initial biopsy reports used to support the diagnosis contained descriptions compatible with a diagnosis of sarcoidosis and/or met the American Thoracic Society/European Respiratory Society/World Association of Sarcoidosis and Other Granulomatous Disorders criteria 6. All microscopic slides from the explanted lungs and mediastinal/hilar regional lymph nodes from these patients were examined by two pathologists (J.M. Oblad and M.N. Koss) who were unaware of any clinical information except for the history of lung transplantation for sarcoidosis. The pathologists were asked to grade the average granuloma burden (lung and lymph nodes) and interstitial fibrosis (lung) individually as follows. Grade 0 (absent): no granulomas or fibrosis detected in the specimen; Grade 1 (mild): less than two granuloma per low-power field (lpf) or occasional foci of fibrosis per low lpf; Grade 2 (moderate): two to five granuloma per lpf or <50% of parenchyma with …